DESCRIPTION (provided by investigator): Exposure to parents' environmental tobacco smoke (ETS) is a significant behavioral health problem that poses serious medical risks for patients who are being treated for cancer. Pediatric cancer patients are at risk for cardiopulmonary and respiratory complications secondary to treatment-related toxicities, and exposure to ETS can exacerbate these adverse health outcomes. Despite these risks, many parents smoke around their child who is undergoing curative cancer therapy. Therefore, the primary objective of this project is to determine the differential efficacy of a parent-based behavioral counseling intervention for reduction of ETS exposure as compared to a Standard Care Control (SCC) condition, as measured by parent report and a biological urine cotinine assay. We will also examine the impact of our intervention on psychosocial variables related to ETS exposure as well as health outcomes in the pediatric cancer patient. Our counseling intervention is a behavioral shaping program that is specifically tailored to account for the features that are unique to the child's diagnosis of cancer and addresses ETS exposure in the context of unique cancer-related circumstances. The components of the intervention include: 1) health counseling focused on ETS-related health problems of children undergoing cancer therapy, 2) behavioral skills counseling involving goal setting, problem solving, shaping, positive feedback and stress management, 3) telephone counseling, 4) physician feedback, and 5) written worksheets to reinforce the counseling sessions. Development of the counseling program is based on the components of the Health Belief Model and Social Learning Theory. Following program development, feedback from a parent advisory panel, and pilot testing, 154 parents of cancer patients with a primary diagnosis of malignancy between the ages of 3 to 17 years, will be randomized to either a Standard Care Control (SCC) or an intervention group. Parents in the SCC group will be advised about the risks associated with ETS exposure and encouraged to stop smoking in the child's environment. Parents in the intervention group will participate in the counseling intervention described above. The impact of our intervention on parent reported ETS exposure and urinary cotinine assays will be evaluated at baseline, 3, 6, 9, and 12 months. Our planned clinical trial may verify the effectiveness of an important clinical service for this vulnerable population that can be adapted for other pediatric oncology settings.